[Diagnosis of neurocysticercosis in patients with epilepsy living in the south-western Dominican Republic]. / Diagnóstico de neurocisticercosis en pacientes con epilepsia residentes en el suroeste de la República Dominicana.

INTRODUCTION: Neurocysticercosis (NCC), a possible cause of epilepsy with limited epidemiological data in the Dominican Republic, is endemic in four provinces in the country's south-western region. This study aimed to determine the association between NCC and epilepsy among people living in these endemic regions, and to obtain preliminary data on the prevalence of NCC in these provinces. PATIENTS AND METHODS: A case-control design was used, consisting of 111 patients with epilepsy with unknown causes, and 60 controls without epilepsy or NCC. The diagnosis of NCC was based on computed tomography and magnetic resonance imaging of the skull, as well as Western immunoblotting for serum antibodies using Taenia solium, following the criteria of Del Brutto et al. RESULTS. NCC was found in 27% of the epileptic patients (n = 30/111) and in 5% of the controls (n = 3/60); the probability of the epileptic patients having NCC was seven times higher than the controls (odds ratio = 7.04, 95% confidence interval: 2.04-24.18; p < 0.001). The participants' sociodemographic characteristics, including their age, sex, level of education, occupation, and province of residence presented no statistical significance in terms of their association with NCC. CONCLUSIONS: This study suggests that NCC is strongly associated with epilepsy in the south-western region of the Dominican Republic, and highlights the need for public health measures to improve the prevention, diagnosis and treatment of both diseases.

TITLE: Diagnóstico de neurocisticercosis en pacientes con epilepsia residentes en el suroeste de la República Dominicana.Introducción. La neurocisticercosis (NCC), una posible causa de epilepsia con datos epidemiológicos limitados en la República Dominicana, es endémica en cuatro provincias de la región suroeste. El objetivo de este estudio fue determinar la asociación entre la NCC y la epilepsia en personas que viven en estas regiones endémicas, así como obtener datos preliminares sobre la prevalencia de NCC en estas provincias. Sujetos y métodos. Se utilizó un diseño de casos y controles compuesto por 111 pacientes con epilepsia de causa desconocida y 60 controles sin epilepsia ni NCC. El diagnóstico de NCC se basó en la tomografía computarizada y la resonancia magnética del cráneo, así como en el inmunotransferencia de Western para anticuerpos séricos contra Taenia solium, siguiendo los criterios de Del Brutto et al. Resultados. Se encontró NCC en el 27% de los pacientes con epilepsia (n = 30/111) y en el 5% de los controles (n = 3/60); los casos de epilepsia tenían siete veces más probabilidades de tener NCC que los controles (odds ratio = 7,04, intervalo de confianza al 95%: 2,04-24,18; p < 0,001). Las características sociodemográficas de los participantes, como la edad, el sexo, el nivel de escolaridad, la ocupación y la provincia de residencia no mostraron significación estadística en cuanto a la asociación con NCC. Conclusiones. Este estudio sugiere que la NCC está fuertemente asociada con la epilepsia en la región suroeste de la República Dominicana, y destaca la necesidad de medidas de salud pública para mejorar la prevención, el diagnóstico y el tratamiento de ambas enfermedades.

Changes of cerebral white matter in patients suffering from Pantothenate Kinase-Associated Neurodegeneration (PKAN): A diffusion tensor imaging (DTI) study.

BACKGROUND: To look for microstructural white matter alterations in patients with dystonia due to Pantothenate Kinase-Associated Neurodegeneration. MATERIAL AND METHODS: We examined 21 genetically confirmed patients and an age-matched group of 21 healthy controls by diffusion tensor imaging. Evaluation of data was performed by tract-based spatial statistics analysis and a voxel-wise comparison of calculated maps of fractional anisotropy. Findings were compared between groups and correlated to the dystonia score of the Burke-Fahn-Marsden Scale (p ≤ 0.05). RESULTS: Patients showed reductions of fractional anisotropy mainly in the periventricular substance surrounding the third ventricle, in the medial part of both putamina and in the frontal white matter including the anterior limbs of the internal capsules and the corpus callosum. Infratentorially, the cerebellar white matter and dorsal parts of the pons and medulla were affected. CONCLUSION: In addition to cortical grey matter changes, we now have a second structural finding pointing to a more widespread affection of cerebral tissue in PKAN dystonia than just the lesion and iron accumulation in the globus pallidus.

Unexpected silent infarctions after embolization of cerebral arteriovenous malformations and fistulas. A diffusion-weighted magnetic resonance imaging study.

We investigated the number and possible causes of clinically silent lesions seen in diffusion-weighted magnetic resonance imaging after embolization of arteriovenous malformations (AVMs) and fistulas using acrylate only or in combination with coils. Included were 19 patients with 18 AVMs and one case of a vein of Galen aneurysm in which 25 interventions were carried out. Results of diffusion-weighted imaging, the appearance of perinidal and distant lesions, were correlated to Spetzler grade, nidus size, flow, number of feeders occluded, rate of nidus occlusion and duration of the intervention. We found seven distant lesions corresponding to non-symptomatic infarcts in the given clinical setting. The only significant correlation between lesion size and parameters analyzed was the degree of nidus occlusion achieved during the intervention. Because most of the lesions presented in cases with a high occlusion rate, they appear to be related to the intention to reach a complete occlusion of the nidus. These results emphasize that the risk involved in eliminating the nidus completely must be reconsidered with special care, particularly in a situation where most high-flow feeders have been occluded.

Involvement of globus pallidus and midbrain nuclei in pantothenate kinase-associated neurodegeneration: measurement of T2 and T2* time.

PURPOSE: To quantify involvement of globus pallidus and two midbrain nuclei (substantia nigra and red nucleus) in Pantothenate Kinase-Associated Neurodegeneration (PKAN). MATERIAL AND METHODS: We performed T2 and T2* weighted imaging with calculation of the corresponding relaxation times on a subset of 5 patients from a larger group of 20 patients with PKAN from the southwest part of the Dominican Republic. Examinations were carried out on a 3T scanner and included a multi-echo spin-echo as well as a multi-echo gradient echo sequence. Results were compared to a control group of 19 volunteers. RESULTS: T2 and T2* weighted sequences showed abnormal signal reduction in the globus pallidus of all patients. On T2* weighted imaging, abnormal signal in the substantia nigra could reliably be detected in 75% of cases, but differentiation from normal was less reliable in T2 weighted scans. Correspondingly, relaxation times differed from normal with very high significance (p < 0.0001) in the globus pallidus, but with with less significance in the substantia nigra (p ≤ 0.03). The red nucleus was not affected. CONCLUSIONS: Signal reduction in the globus pallidus, which probably is due to abnormal accumulation of iron, is severe in PKAN and can be differentiated from normal with high reliability. The substantia nigra is affected to a lesser degree, and the red nucleus is not involved. The reason for this selective susceptibility of normally iron-rich brain structures for pathological accumulation of iron remains speculative. Our quantitative results might be helpful to assess the value of an iron chelation approach to therapy.

Motor activation in patients with Pantothenate-Kinase Associated Neurodegeneration: a functional magnetic resonance imaging study.

BACKGROUND: In a variety of dystonias, functional magnetic resonance imaging has shown deviations of cortical and basal ganglia activations within the motor network, which might cause the movement disturbances. Because these investigations have never been performed in secondary dystonia due to Pantothenate-Kinase Associated Neurodegeneration, we report our results in a small group of such patients from the Dominican Republic. METHODS: Functional magnetic resonance imaging was carried out in 7 patients with a genetically confirmed mutation of the PANK2 gene and a non-affected control group (matched pairs) using an event-related motor activation paradigm (hand movements). RESULTS: Compared to the control group (p ≤ 0.01), patients showed a larger amount of activated voxels starting in the contralateral cerebellum and contralateral premotor cortex 2 s before the actual hand movement. Whereas these "hyperactivations" gradually diminished over time, activations in the contralateral primary motor cortex and the supplementary motor area peaked during the next second and those of the contralateral putamen at the time of the actual hand movement. In a multiple regression analysis, all these areas correlated positively with the degree of dystonia of the contralateral arm as judged by the Burke-Fahn-Marsden-scale (p ≤ 0.001). CONCLUSION: As in other forms of dystonia, the increased activations of the motor system found in our patients could be related to the origin of the dystonic movements. Because in this condition the primary lesion affects the pallidum, a defect of the feed-back control mechanism between basal ganglia and cortex might be the responsible factor.

Measurement of blood flow in arteriovenous malformations before and after embolization using arterial spin labeling.

The assessment of shunt reduction after an embolization of an arteriovenous malformation (AVM) or fistula (AVF) from conventional angiography is often difficult and may be subjective. Here we present a completely non-invasive method using magnetic resonance imaging (MRI) to measure shunt reduction. Using pulsed arterial spin labeling (PASL), we determined the relative amount of signal attributed to the shunt over 1.75 s and 6 different slices covering the lesion. This amount of signal from the shunt was related to the total signal from all slices and measured before and after embolization. The method showed a fair agreement between the PASL results and the judgement from conventional angiography. In the case of a total or subtotal shunt occlusion, PASL showed a shunt reduction between 69% and 92%, whereas in minimal shunt reduction as judged by conventional angiography, the ASL result was -6% (indicating slightly increased flow) to 35% in a partially occluded vein of Galen aneurysm. The PASL method proved to be fairly reproducible (up to 2% deviation between three measurements without interventions). On conclusion, PASL is able to reliably measure the amount of shunt reduction achieved by embolization of AVMs and AVFs.

Association between cingulum bundle structure and cognitive performance: an observational study in major depression.

BACKGROUND: Major depression can be regarded as a systemic neurobehavioral disorder resulting from dysfunction of the limbic-cortical networks. The cingulum bundle represents a major association fiber tract of those networks. The aim of our study was to determine the association of brain structural tissue markers of the cingulum bundle and cognitive function in patients with major depression. METHODS: Region-of-interest-based analyses of the middle-anterior and middle-posterior cingulum bundle fractional anisotropy (FA) and mean diffusivity (MD) using color-coded diffusion-tensor imaging and neuropsychological assessment in 14 patients with major depression. RESULTS: FA of the middle-anterior and middle-posterior cingulum bundle was significantly correlated to the performance in a planning and divided attention task. Furthermore, MD of the middle-posterior cingulum bundle was significantly correlated to a planning task. There was no significant correlation between FA and MD of the cingulum bundle and selective attention or memory. CONCLUSIONS: Brain structural tissue markers of the middle-anterior and middle-posterior cingulum bundle were found to be associated with executive functioning and divided attention in patients with major depression. Disconnection within the limbic-cortical networks may underlay cognitive dysfunction in major depression.

[A capillary-based perfusion phantom for the simulation of brain perfusion for MRI]. / Ein kapillarbasiertes Phantom zur Simulation der Gehirnperfusion mit der Magnet-Resonanz-Tomografie.

PURPOSE: The measurement of the CBF is a non-standardized procedure and there are no reliable gold standards. This abstract shows a capillary-based perfusion-phantom for CE-DSC-MRI. It has equivalent flow properties to those within the tissue capillary system of the human brain and allows the validation of the Siemens Perfusion (MR) software. MATERIALS AND METHODS: The perfusion phantom consists of a dialyzer for the simulation of the capillary system, a feeding tube for simulation of the AIF and a pulsatile pump for simulation of the heart. Using this perfusion phantom, the exact determination of the gold standard CBF due to the well-known geometry of the phantom is easy. It was validated based on different perfusion measurements. These measurements were investigated with standard software (Siemens Perfusion MR). The software determined the CBF within the capillary system. Based on this CBF, a comparison to the gold standard was made with several different flow speeds. After AIF selection, a total of 726 CBF data points were automatically extracted by the software. RESULTS: This results in a comparison of the gold standard CBF to these 726 CBF values. Therefore, a reproducible and reliable deviation estimation between gold standard CBF and measured CBF using the software was computed. It can be shown that the deviation between gold standard and software-based evaluation ranges between 1 and 31 %. CONCLUSION: There is no significance for any correlation between flow speed and amount of deviation. The mean measured CBF is 11.4 % higher than the gold standard CBF (p-value < 0.001). Using this kind of perfusion-phantom, the validation of different software systems allows reliable conclusions about their quality.

Sildenafil improves scotoma after posterior cerebral infarctions: a case report.

A 65-year-old man had an embolic stroke of both posterior cerebral arteries in 2002. Two years later he noted rapid improvement of the residual bilateral inferior quadrant anopia whenever he took 25 mg sildenafil. The improvement of scotomas was verified by visual field examinations and persisted reproducibly for 3-7 days. An overlay of a subtraction of functional magnetic resonance imaging (MRI) during visual stimulation before and after medication onto a T1-weighted MRI of the patient revealed additional activations along the margins of the old cerebral infarctions. These findings and the additional results of a perfusion MRI suggest that phosphodiesterase 5 inhibitors may prove beneficial in the rehabilitative course after ischemic strokes.

Anatomical correlates of ocular motor deficits in cerebellar lesions.

Humans are able to stabilize the images of moving targets on the retina by means of smooth pursuit eye movements. After the pontine level, all smooth pursuit pathways pass through the cerebellum. Previous animal studies gave evidence that two specific lesion sites within the cerebellum cause smooth pursuit disorders: those of the flocculus/paraflocculus and the vermis including lobule VI, VII, the uvula and the deep cerebellar nuclei. To date, there have been only a few lesion studies in patients with smooth pursuit disorders that do not allow direct comparison with a control group. In the present study, new lesion mapping techniques determined which cerebellar structures were involved in patients with deficits of smooth pursuit eye movements, slow phase of optokinetic nystagmus (OKN) and fixation suppression of vestibulo-ocular reflex, i.e. in eye movements that are considered to belong to the smooth pursuit system. The aim was to elucidate whether there is an anatomical and clinical link between these different eye movement disorders. Seventeen patients with acute, mainly unilateral cerebellar infarctions and an intact gain of the smooth pursuit system were compared with 11 patients with cerebellar lesions and deficient gain of sinusoidal smooth pursuit eye movements by means of lesion-mapping imaging. In addition, lesion analyses were conducted in subgroups with impaired fixation suppression of vestibulo-ocular reflex and deficient gain of the slow phase of the OKN. The uvula and partly the vermal pyramid were found to be the structures commonly damaged in patients with deficient gain of the horizontal sinusoidal smooth pursuit eye movement, of the slow phase of the OKN and impaired fixation suppression of vestibulo-ocular reflex; and were less involved in patients with intact smooth pursuit system. The present data give evidence for an anatomical link between sinusoidal smooth pursuit eye movements, fixation suppression of vestibulo-ocular reflex and the slow phases of OKN implying that the uvula and the vermal pyramid are important structures for generating slow phases within the smooth pursuit network in humans.

[Injury of ICA during endonasal sinus surgery and management by endovascular stent application]. / Verletzung der ACI bei Nasennebenhöhlenoperation und Management durch endovaskuläre Stentapplikation.

BACKGROUND: Injury of the internal carotid artery (ICA) during endonasal sinus surgery is rare but a life-threatening situation for the patient. For adequate treatment endovascular therapy as embolization or balloon occlusion is usually performed although there is a high risk of irreversible neurological deficits. CASE REPORT: We report on a twenty-five-year-old female patient with acute exacerbated chronic polyposis nasi suffering from an injury of the ICA during endonasal sinus surgery. After intraoperative identification of the site of hemorrhage the massive bleeding could temporarily be controlled by a nasal pack. The woman was immediately transferred to a neuroradiological department. After angiographic localization of the vessel defect the bleeding could be stopped by application of a vascular stent without any neurological deficits during or after the procedure. Anatomical characteristics of the ICA in the sphenoid sinus, and recommended emergency treatment and preventive measures are discussed. CONCLUSION: Although vascular stents are difficult to place in the intrasphenoidal course of the ICA, it provides an effective closure of the vascular injury and above all a sufficient cerebral perfusion, therefore, the risk of neurological defects can be reduced.

Minimally invasive cerebral cavernoma surgery using keyhole approaches - solutions for technique-related limitations.

Cavernomas are often small in size and located in difficultly accessible regions. Preoperative identification of the ideal surgical approach as well as the precise intraoperative implementation of the surgical plan are of critical importance for successful surgery. While aiming for minimally invasive surgical techniques and maximally effective cavernoma resection, we envisaged that employing a combination of precise and technically sophisticated virtual reality surgery planning, modern navigation systems with augmented reality features and endoscope-assisted surgical techniques should contribute to achieve this goal. Between December 2002 and November 2005, 66 patients were operated on for cerebral cavernomas in our department. In 23 cases surgery planning was done by using a virtual reality planning system, neuronavigation was used in 43 cases and the intraoperative augmented reality feature was used in 16 cases. 10 patients were operated by using the endoscopic assisted surgical technique. Complete resection was achieved in all cases. Using all nowadays available surgical tools, cerebral cavernomas can be operated with minimally invasive techniques and with excellent results.

Diagnostic utility of different MRI and MR angiography measures in Fabry disease.

BACKGROUND: Neurologic hallmarks of Fabry disease (FD) include small fiber neuropathy as well as cerebral micro- and macroangiopathy with premature stroke. Cranial MRI shows progressive white matter lesions (WML) at an early age, increased signal intensity in the pulvinar, and tortuosity and dilatation of the larger vessels. To unravel the most promising imaging tool for the detection of CNS involvement in FD we compared the diagnostic utility of the different MR imaging findings. METHODS: Twenty-five clinically affected patients with FD (age 36.5 +/- 11.0) and 20 age-matched controls were investigated by structural MRI, MR angiography, and diffusion tensor imaging (DTI). Individual WML volumes, global mean diffusivity (MD), and mean cerebral artery diameters were determined. RESULTS: Using receiver operating characteristic analyses, enlarged diameters of the following cerebral arteries significantly separated patients with FD from controls: middle cerebral artery: area under curve (AUC) = 0.75, p = 0.005; posterior cerebral artery: AUC = 0.69, p = 0.041; carotid artery: 0.69, p = 0.041; basilar artery: AUC = 0.96, p < 0.0005. A total of 87% of the individuals were correctly classified by basilar artery diameters (sensitivity 95%, specificity 83%). WML volumes and global MD values did not significantly separate patients from controls. CONCLUSIONS: With an accuracy of 87%, basilar artery diameters were superior to all other MR measures for separating patients with Fabry disease (FD) from controls. Future studies should adopt basilar artery measurements for early detection and monitoring of brain involvement in FD. Moreover, further investigations should reveal if the dilated vasculopathy in FD could be a screening marker to detect FD in a cohort of other cerebrovascular diseases, especially in cryptogenic stroke.

Neural correlates of hemispheric dominance and ipsilaterality within the vestibular system.

Earlier functional imaging studies on the processing of vestibular information mainly focused on cortical activations due to stimulation of the horizontal semicircular canals in right-handers. Two factors were found to determine its processing in the temporo-parietal cortex: a dominance of the non-dominant hemisphere and an ipsilaterality of the neural pathways. In an investigation of the role of these factors in the vestibular otoliths, we used vestibular evoked myogenic potentials (VEMPs) in a fMRI study of monaural saccular-otolith stimulation. Our aim was to (1) analyze the hemispheric dominance for saccular-otolith information in healthy left-handers, (2) determine if there is a predominance of the ipsilateral saccular-otolith projection, and (3) evaluate the impact of both factors on the temporo-parieto-insular activation pattern. A block design with three stimulation and rest conditions was applied: (1) 102 dB-VEMP stimulation; (2) 65 dB-control-acoustic stimulation, (3) 102 dB-white-noise-control stimulation. After subtraction of acoustic side effects, bilateral activations were found in the posterior insula, the superior/middle/transverse temporal gyri, and the inferior parietal lobule. The distribution of the saccular-otolith activations was influenced by the two factors but with topographic disparity: whereas the inferior parts of the temporo-parietal cortex were mainly influenced by the ipsilaterality of the pathways, the upper parts reflected the dominance of the non-dominant hemisphere. This is in contrast to the processing of acoustic stimulation, which showed a predominance of the contralateral pathways. Our study proves the importance of the hemispheric preponderance also in left-handers, which is of relevance in the superior parts of the insula gyrus V, the inferior parietal lobule, and the superior temporal gyri.

Cortical representation of saccular vestibular stimulation: VEMPs in fMRI.

Short tone bursts trigger a vestibular evoked myogenic potential (VEMP), an inhibitory potential which reflects a component of the vestibulocollic reflex (VCR). These potentials arise as a result of activation of the sacculus and are expressed through the vestibulo-collic reflex (VCR). Up to now, the ascending projections of the sacculus are unknown in humans, only the representation of the semicircular canals or the entire vestibular nerve has been demonstrated. The aim of this study was to determine whether a sacculus stimulus that evoked VEMPs could activate vestibular cortical areas in fMRI. To determine this, we studied the differential effects of unilateral VEMP stimulation in 21 healthy right-handers in a clinical 1.5 T scanner while wearing piezo electric headphones. A unilateral VEMP stimulus and two auditory control stimuli were given in randomized order over the stimulated ear. A random effects statistical analysis was done with SPM2 (p<0.05, corrected). After exclusion of the auditory effects, the major findings were as follows: (i) significant activations were located in the multisensory cortical vestibular network within both hemispheres, including the posterior insular cortex, the middle and superior temporal gyri, and the inferior parietal cortex. (ii) The activation pattern was elicited bilaterally with a predominance of the right hemisphere in right-handers. (iii) Saccular vestibular projection was predominantly ipsilateral, whereas (iv) pure acoustic stimuli were processed with a predominance of the respective contralateral and mainly in the left hemisphere. This is the first demonstration by means of fMRI of the cortical representation of the saccular input at cortical level. The activation pattern is similar to that known from the stimulation of the entire vestibular nerve or the horizontal semicircular canal. Our data give evidence of a task-dependent separation of the processing within the vestibular otolith and the auditory systems in the two hemispheres.

Voxel based analyses of diffusion tensor imaging in Fabry disease.

BACKGROUND: Fabry disease (FD) is a lysosomal storage disorder associated with marked cerebrovascular disease. Conventional MRI shows an extensive load of white matter lesions (WMLs) which may already be present at an early stage in the disease. OBJECTIVE: Investigator independent and sensitive quantification of structural changes in the brain in clinically affected men and women with FD. METHODS: We performed a voxel based analysis of diffusion tensor images (DTI) in 25 patients with FD and 20 age matched normal controls. RESULTS: DTI revealed significant increases in cerebral white matter mean diffusivity (MD) in patients with FD, which were pronounced in the periventricular white matter. Even the subgroup of patients without significant WMLs load (n = 18) showed increased diffusivity in the cerebral white matter. In gray matter areas, MD elevation was detected only in the posterior part of the thalamus, independent of the visible pulvinar alterations on T1 weighted images. Voxel based fractional anisotropy measurements did not differ significantly between patients and controls. CONCLUSIONS: The present study demonstrates the clinical feasibility of voxel based analysis of DTI as a sensitive tool to quantify brain tissue alterations in FD. The pattern of increased brain tissue diffusivity is probably due to microangiopathic alterations, mainly affecting the long perforating arteries.

Cerebral activation in patients with somatoform pain disorder exposed to pain and stress: an fMRI study.

Patients with somatoform pain disorders are supposed to suffer from an early acquired defect in stress regulation. In order to look for common alterations of the pain- and stress-responsive cortical areas, we prospectively recorded cerebral activations induced by pin-prick pain, by cognitive stress and emotional stress using functional magnetic resonance imaging (fMRI) in a group of 17 patients and an age-matched control group. In addition, the hippocampal volumes of both groups were measured. Patients showed increased activations of the known pain-processing areas (thalamus, basal ganglia, operculo-insular cortex), but also of some prefrontal, temporal and parietal regions during first pain exposure and of temporal and parietal areas during cognitive stress, but reduced activations during emotional stress. In contrast to these functional differences, hippocampal volume was not significantly reduced in patients. Although the superior temporal gyrus was the only common area of an "overactivation" in patients in the pain and stress condition, findings of our study support the current concept of mechanisms involved in somatoform pain disorders: central processing of pain and of cognitive stress is increased in patients possibly due to exaggerated memory and/or anticipation of pain exposure and to a disturbance of stress-regulating systems which has to be worked out on a cortical level in more detail. Our finding of a reduced responsiveness to emotional stress is surprising, but not contradictive to these results because some sort of neglect or coping mechanisms may have developed over time as a response to early adversities.

Combined spike-related functional MRI and multiple source analysis in the non-invasive spike localization of benign rolandic epilepsy.

OBJECTIVE: To localize the irritative zone in children by combined spike-related fMRI and EEG multiple source analysis (MSA) in children with benign rolandic epilepsy. METHODS: Interictal spikes were averaged and localized using MSA, and source locations were displayed in the anatomical 3D-MRI in 11 patients (5-12 yrs, median 10). Interictal spikes were additionally recorded during the fMRI acquisition (EEG-fMRI), and the fMRI sequences were correlated off-line with the EEG spikes. RESULTS: MSA revealed an initial central dipole in all patients, including the face or hand area. A second dipolar source was mostly consistent with propagated activity. BOLD activations from EEG-fMRI, consistent with the locations of the initial dipoles, were found in four patients. We found additional large areas of BOLD activations in 3 of these subjects extending into the sylvian fissure and the insula. These were identified as propagated activity by MSA using the short time differences in the source waveforms. CONCLUSIONS: MSA provided reliable localization of the spike onset zone in all children with benign rolandic epilepsy. Using the combination of EEG-fMRI and MSA we were able to discriminate the spike onset zone from propagated epileptiform source activity, using the spatial resolution of the EEG-fMRI technique and the temporal resolution of the MSA. However, the sensitivity of the EEG-fMRI technique was low and further improvements of the technique are warranted. SIGNIFICANCE: This study shows that a combination of EEG-fMRI and MSA may be a powerful tool to describe the irritative zone of patients with idiopathic focal epilepsies. Clinical studies in patients with non-idiopathic focal epilepsies may clarify whether both techniques can be used as complementary clinical tools to localize the onset of interictal epileptic activity in focal epilepsies.

[Pathophysiological aspects of brain structural disturbances in patients with Fabry disease: literature review]. / Pathophysiologische Aspekte hirnstruktureller Veränderungen bei Morbus Fabry: Literaturübersicht.

Fabry Disease (FD) is a rare X-linked lysosomal storage disorder caused by deficiency of alpha-galactosidase A (alpha-GAL) enzyme activity. Neutral glycosphingolipides (esp. Gb3) accumulate in lysosomes of several tissues, particularly in vascular endothelium and smooth muscle cells. Cerebral manifestations that might be mainly due to progressive cerebrovascular dysfunction, are one major and often life-threatening burden of the disease. We reviewed the present literature concerning brain structural alterations in FD and discuss the possibly relevant underlying pathophysiological aspects of these disturbances. Cerebrovascular events (TIA, stroke) occur in FD at a rather early age. In female FD patients who were considered to be less affected "carriers" for a long time, the prevalence of cerebrovascular events seems to be at last as high as in male patients. In structural imaging white matter lesions (WML) can be found frequently even in young FD patients. In a recent study clinically equally affected men and women with FD showed a comparable severity of WML load. Different pathophysiological aspects of cerebral angiopathy and WML development are discussed against the background of current concepts (e. g. accumulation of Gb3 in vascular endothelium with consecutive cell proliferation and luminal stenosis, acceleration of focal intravasal pressure and disturbances of vascular auto-regulation). Pathological increase of pulvinar signal in T1-weighted MRI has also been described in FD. This finding was assumed to be caused by calcification as a consequence of disturbed local circulation. To enhance our knowledge about the relevant neurobiological processes the authors propose a more sensitive and early detection of brain structural changes in FD. New brain structural MRI methods such as diffusion-tensor imaging could provide a pattern of ultrastructural changes even in young patients without visible WML. This strategy could be as well useful for quantification of possible effects of the enzyme replacement therapy on brain structural alterations in FD. Based on recent data a systematic FD-screening by measuring Gb3 in urine of young patients with cryptogenic stroke should be discussed. Basically in such cases FD should be clinically considered.

Distribution characteristics, reproducibility, and precision of region of interest-based hippocampal diffusion tensor imaging measures.

BACKGROUND AND PURPOSE: For adequate interpretation of diffusion tensor imaging (DTI) parameters empirical distribution characteristics, precision, and reproducibility should be known. The present study investigated distribution and reliability parameters of hippocampal fractional anisotropy (FA) and mean diffusivity (MD). METHODS: FA and MD values were averaged in hippocampal regions of interest in 20 subjects (10 women and 10 men; age range, 25-69 years). Regions of interest were manually placed bilaterally by one investigator at 2 occasions, and by a second independent investigator. Sample distributions of FA and MD values were compared with normal distributions. Intraclass coefficients (ICCs), standard errors of measurement (SEMs), and coefficients of variation (CVs) with confidence intervals (CI95s) were computed. RESULTS: The results did not show any deviation of averaged FA (0.237 +/- 0.017) and MD (775 +/- 28 microm2/s) values from normal distribution. Intraobserver reliability (ICC > or = 0.90) and precision (CV < or = 3.5%) were high for all measures. Interobserver reliability reached values of ICC > or = 0.84 and CV < or = 4.1%. FA yielded lower precision (CV 2.2-4.1%) than MD (CV 1.3-2.5%), CI95s were around +/-0.015-0.020 and +/-25-30 microm2/s for FA and MD, respectively. FA differences of 0.020-0.030 and MD differences of 40-50 microm2/s can be assumed to reflect reliably distinct values in hippocampal regions. CONCLUSION: The results are in line with previous reports on reliability of DTI measures by using different designs and methodology. Notwithstanding the difficulties associated with region of interest-derived DTI measurements in hippocampal regions, the present approach provides estimates of distribution characteristics and precision applicable to routine assessments of DTI parameters in clinical and research context.